Arsenic derivatives and process of preparing same



' members of the classes-OH, H,

Patented Feb. 3, 1948 ARSENIC DERIVATIVES ANDPROCESS OF PREPARINGISAME Cliff Struthers Hamilton, Lincoln, Nebn, and

Clarence Kenneth Banks, Detroit, Mich., as-

signors to Parke, Davis & Company, Detroit, Mich, ajcorporation of Michigan No'llrawingr 'ldpplleatioii June 19, 1943, I Serial No. 491,564

13 Claims (01. 260-242) 1 4. Arsenical derivatives of anilinopyrimidines have not been known previously. We have, now found that anilinopyrimidines substituted in the benzene ring by arsenic groups have unusual pharmacological and chemotherapeutical properties and are of value as trypanocides and as intermediates in the production of other compounds of' pharmaceutical interest.

The compounds of the invention are alsounusual in that very small doses are suflicient for the treatment of experimental trypanosoniiasis.=-;

This is of advantage in that it thereby becomes unnecessary to administer relatively large quantities of toxic arsenic compound, as was previously required, in order to get satisfactory therapeutic efiects.

The new compounds or the invention have the iormula,

where A is a member of the class the arsono group (AsOaI-Iz) the salts of arsono groups and --AsO3M2 where M is a basic s'alt -forming group, such as an alkali metal oran ammonium or substituted ammonium radical, such as alkylammonium, aralkylammonium, cycloalkylammonium, etc), the arsinoso group or its hydrate (AsO or As(OH) 2), the dihaloarsinoso group (AsHalz Where Hal represents chlorine, bromine or iodine) the arsine sulfide group and the various dithloarsenite groups, -As(SR.) 2, where R is an alkyl radical directly attached by a methylene linkage to the sulfur atom of SR and may or may not contain the group CONH-, said radical being substituted byone of COOH and -COOM and substituted or not by one or more of NH2 and NH2.HA' whenever R containsCO0I-I, but by one or more of NH2 only when R contains COOM, the group M being a basic salt-forming group, as already mentioned, A being the anion of an acid having a dissociation constant of about 10 or more, such as hydrochloric or hydrobromic acid, sulfuric acid, phosphoric acid, tartaric acid, etc., where B is a member of the class, H, NOz, OH, NI-Iz,

. hydroxyalkoxy and a halogen of the class chlorine, bromine and iodine, and where X and Y are ,-N.H2, m d e halogen (-,-C1 or Br) lower alkyl such as methyl, ethyl, butyl, etc. and lower alkoxy such as methoxy, ethoxy, etc., and where P is a memberbf the class -H, Cl, Br, NO2 and NH2. A The new compounds may be prepared by two general methods. In each of these, whenever a .halopyrimidine is reacted with an aminobenzenearsonic acid, it is preferred to employ an acidic reaction medium, for example in accordance with the procedure describedin copending application of Clarence Kenneth Banks, Serial No. 464,250, filed November 2, 1942.

7 General method 1 Two compounds having the following forma arereacted, ASOrH:

where W is a member of the class middle halogens and NH2. where one of W and Z is an amino group and the other is a halogen of the classclilbrine and bromine and where B, X, Y and P are as previously defined. These two compounds are reacted in aqueous or non-aqueous solvents, in the presence of acid or alkali when advantageous for completion of the particular reaction involved, to give a desired compound which may be further modified at the arsenic group to give other members of the class A by application of various chemical procedures, such as those illustrated further herein. By way of illustration, 8. benzenearsonic acid containing an active halogen can be reacted with an amino pyrimidine '(e. g. 3-nitro-4-bromobenzene arsenic acid and 2-aminopyrimidine to give 3-nitro-4-pyrimidyl-aminobenzenearsonic acid), or, an aminobenzenearsonic acid may be reacted with a chloroor a bromopyrimidine (e. g. p-arsanilic acid and 2- amino--chloropyrimidine to give 2-amino-4--(4'- arsonoanilino) pyrimidine hydrochloride).

General method 2 Two compounds are reacted together having the following formulas, v

hilHz o, f N g and Hal- J L Y N pyrimidine nuclei,

'2 ,4- diaminopyrimidine lf2 amino-4-methoxypyrimidine 2-chloro-4-methoxypyrimidine 2'-methox y-4-chloropyrimidine 2-amino-4-chloro-G-methylpyrimidine 2-amino-l-methoxy-G-methylpyrimidine 4-.amino-2-chloro-6-methylpyrimidine 4-amino-2-methoxy-B-methyIpyrimidine where B, X, Y and P are groups which have already been defined, where Hal is a middle halogen (chlorine or bromine) and C is nitroj amino; acylamino or other group capable ;of' being con: verted to' an amino group, for example by reduction or hydrolysis, said group C being in the meta or para position to the amino group. These two compounds are reacted according to the-process described in the above mentioned applicationzof' Clarence Kenneth Banks and the product obtained has the formula, v

n D L group C of this product is then converted to -'the amino group, wherenecessary, and then the "compoundflconverted by diazotization. of the amino group in-aqueous or non-aqueous solvent and coupling with aninorganic arsenic compound (e. g, Bart or Scheller-Bart reaction) to give one of our new pyrimidine substituted arsonic acids coming under the general formula first given above. fIfhe arsonic acids can be further treated to modify the arsenical grouping as'mentioned above under Method 1. If acidaddition salts of the amino products are desired,-it is an easy matter to react themwith anacid, HA, to convert the group -N H., connecting the benzene and oup where Ais already defined. l

Sm e of the p rimidine starting materials that are:

' :2 arninoe4- chloropyriinidlne J '-amino-2-chloropyrimidine 2,4-dichloropyrimidine 2,4- diamino- S-methylpyrimidine 2,4-dichloro-G-methylpyrimidine 2,4,6-trichloropyrim'idine -2-amino-4,6-dichloropyrimidine 2,4-diamino-fi-chloropyrimidine 4-amino-2,6-dichloropyrimidine 2-ch1oro-5-nitropyrimidine 2-ch1oro-5-amin0pyrimidine 2,4-dichloro-5-bromopyrimidine. 2,4-dich1oro-6-methoxypyrimidine 1 2-methoxy-4-amino 6 chloropyrimidin' 2,4-dichloro-5-nitropyrimidine 2-chloro-4-amino-5-nitropyrimidine into the acid addition "'salt Examples of arsonic acids for Method 1 that may be used to react with the pyrimidine compounds listed and having the general formula ay be used in Methods 1 and 2 and havingthe lformula v 4.

iii-'liisaninc acid samples ofcornpounds tri ent which may be used in 2 a re:

p- P henylene diamine in-Phenylen diami'ne p-Aminoaceta'nilide m-Aminoacetam'lide p-;l l itrpaniline p-Aminoaz oben'zene details tor. reacting the cornboundsi eted will be evident to those skillediin the art by reference'to the following detailed example.

Emmi

"p-Arsanilic acid (40 g);-2-aniino-4-chloropyrimidine (20g), hydrochloric acid i(5 ml.) and ethylhexyl alcohol (traceasa defoaming agent) are refluxed in'water (21;) until complete solution occurs (about 15-minutes) and then fori15 minutes more. Thesolution 'is treated TWith.v activated charcoal while hot; filtered and concentratedhydrochloric acid (200 ml.) added and the solution cooled. A white "crystalline mass "ishdeposited which may be filtered ofi andirecr'ystalliz ed from dilute hydrochloric acid. The prodnot, after drying in vacuo over a dehydrating agent is a white, crystalline substance, slightly soluble in Water, melting above 250 C. and giv- 'ing -an arseno test with-hypophosphorousacid. It is insoluble inorganic solvent, cohtains'ionic ihalogn and analyzes for. 21.58% arsenic .lhe

1 yield is 53 g: or-nearly thetheoretic'al amountiexpected. This compound is 2-amino-4-(4-arsonoairness N J-Nm N Z-amino--(4-arsonoanilino) pyrimidine hydrochloride This procedure may be varied by using Z-amin-4-br0mopyrimidine in place of the chloro compound.

The volume of water is not critical and may be varied within wide limits, this particular volume being convenient for handling. The amount of hydrochloric acid used may be varied several fold or omitted, although its absence means that the reaction will require more time for completion. Basic condensing agents may be used but the yields will thereby be decreased and the impurities will be increased. Other acids may be used in the condensation, particularly mineral acids and the stronger organic acids. Mixed solvents may be used, such as alcohol-water, acetonewater, acetone-alcohol, dioxane-water, and other similar combinations without materially affecting the result.

The hydrochloride obtained above may be treated in warm aqueous solution or suspension with alkalies, such as ammonium hydroxide or sodium hydroxide, until the mixture is neutral to Congo red paper. The resulting white precipitate which is filteredoff and dried is an arsonic acid, soluble in alkali and melting above 250 C. The product is a dihydrate-and analyzes for 21.67% arsenic. The compound is the dihydrate of 2-amino-4-(4'-arsonoanilino) pyrimidine. The theory for arsenic is, 21.65%. The yield is quantitative.

i os r I 2-amino-4-(4'-ars0noanilin0) pyrimidine diliydrate This compound may be further dried to give the anhydrous material The arsenic acid obtained above is suspended in 250 ml. of water and-sufiicient sodium hydroxide to give a solution is added (two equivalents) The solution is filteredand theclisodium salt thus formed is crystallized out of solution by the addition of alcohol and acetone or alcohol and ether. This salt is a white, crystalline prodnot which may be variously hydrated. It is of theory or 52 g. On drying arsenic.-

Theory Lis .ful arsonoanilinopyrimidines.

6 21.16%. The compound/is. disodium 2-amino- 4-(4'-arsonoanilino) pyrimidine.

ASOsNM Disodimn z-amino-i-(y-arsonoenilino) pyrimidine As will be readily understood by one skilled in the art, if one wishes to have a different arrangement of groups in the benzene and pyrimidine nuclei or if difierent groups are desired, the reactants are so chosen to contain these groups and in such positions as desired.

From the foregoing descriptions it will be seen that the present invention provides new and use- Other and more specific examples of these new compounds are shown below:

2-amino-4-(4-arsono-3-hydroxyanilino) pyrimidine AsOsHz I oonionzon Nah I.

. N i V I 2-smino-4-(4'-arsono-3-B-hydroxyetboxy-aniline) pyrimidine 2-amino-i-(5-msono-2-hydroxy-anilinol pyrimidine l NH 2-amino-4-(5-arsonc-2-p-hydroxycthoxya'nilino) pyrimidine Aso'iii ITIH 2-amino-4-(3-arsonoanilino) pyrimidine AsOzHg 2-amino-4-(2-arsonoanilin0) pyrimidine AS 3H2 2,4-diamino-6-(4-arsonoanilino) pyrimidine IIIH HzN- Jam, N

ZA-diamino-fi-(4-arsono-3-hydroxyanilino) pyrimidine 01 J-NH:

2-amino-4-(4-arsonoanilino)demure-pyrimidine zFiS 0 :Hi

2-amino-4-(4-arsonoanilino)-6-methoxy-pyrimidine "acetanilider p-phenylene diamine or p-aminoazo- 2-amino-4-(4-arsonoanilino) -6- methyl-pyrimidine i is'oaH,

2-amino-4-(4-arsono-2'-hydroxy-anilino) pyrimidine NH: 7 V

, LN ASOsH: V V H 4-amin'o-2-(4 arsonoanllino) pyrimidine ITIHQ I V N. J-NQASCHHQ N i 2-amino'-4-(4-arsono-3-hydroxy-anilino) pyrimidine" 2-(4-arsonoani1ino)-5-nitropyrimidine Example 2 ,The 2-amino-4-(4'-aminoanilino) pyrimidine (20 g.) starting material can beprepared by Jfcondensing p-nitro-aniline and 2amino-4-chloro-pyrimidine by the process described in" the contending application of Clarence Kenneth' Banks and reducing the resultant condensate with hydrogen and Raney nickel catalyst. The starting materialmay also be obtainedby substituting for p.-nitro'-a-niline such substances as p-aminobenzene and treating the resulting condensate withappropriate reagents to obtain a p-aminobenzene grouping, as would be apparent to one skilled in the-art. Th 2-amino-4-(4'-amino- 9 aniline) pyrimidine-is dissolved in. dilute hydrochloric acid and diazotized with one-tenth-mole of sodium nitrite. The diazonium solution is coupled with 0.15 mole of sodium arsenite solution containing a trace of copper salts. The coupled,

solution is freed of tars and the arsenical precipitated with hydrochloric acid. It is Z-amino 4-(4'-arsonoanilino) pyrimidine hydrochloride, the same product whose preparation is disclosed in Example 1.

' Example 3 3-nitro-4-bromobenzenearsonic acid (18 g.) and 2-aminopyrimidine (10.5 g.)' are dissolved in water and made basic to litmus paper with potassium hydroxide solution. The solution is refluxed in an oil bath for'fi've hours while addsulfur dioxide gasis passed through. A trace of potassium iodide is added and the sulfur dioxide,

continued until no iodine color appears on standing. After standing and cooling for twenty-four hours, the product is filtered oil and purified by solution in hot water and reprecipitation with hydrochloric acid. It is a white crystalline prodnot, not melting below 250 C. Analysis shows 20.31% arsenic, theory requires 20.38%. It is 2- ing additional small quantities of potassium hydroxide solution at half-hour intervals. The solution is cooled and acidified with hydrochloric acid to Congo red paper. The yellow solid which separates is recrystallized twice from hot, water and dried at 60 C. The product iseasilysoluble in water, even in the cold. On heating the'dry solid, liquid crystals are formed at 148-156 C.

which melt to a clear liquid at l60-l63 C. The

product analyzes for 22.18% arsenic. The theory requires 22.03% arsenic. It "is 2-(4-arsono-2'- nitro-anilino) pyrimidine.

J-N ASOiH: I 7 v H 2-(4-arsono-2'-nitro-anilinol pyrimidine ."Ihe same product is formed if the reaction of 3-nitro-4-bromobenzenearsonic acid and 2-aminopyrimidine is run in amyl alcohol or similar solvent using copper powder and sodium or potassium acetate as condensing agents;

Example 4 The product of Example 3 is dissolved in dilute sodium hydroxide and hydrogenated, using Raney nickel catalyst and molecular hydrogen at forty pounds pressure and room temperature. After removing the catalyst, the solutionjs.acidified with hydrochloric acid ,togivea brownish mate;

rial which is 2-(4-arsono-2'-aminoanilino) pyrimidine.

, N -r gssoanl n i N112 2-(2-amino 4-arsonoanilinol pyrimidine By the same method, nitro compounds obtained under Example 1 may be reduced to amino compounds For instance, 2 (4'-arsonoani1ino),--

E nitrO-pyrimidine gives 1 Les , N l H 5-amino-2-(4'-er son6anilino) pyrimidine Example 5 z-amino-i-(4'-arsonoanilino) pyrimidine disodium salt is dissolved in a liter, of water and concentrated hydrochloric acid-added (about ml.). .'The suspension formedis warmed while 2-amiuo-i-(4- licl1loroarsinosoanilino) pyrimidine hydrochloride When the above described product is dissolved in hot water and the solution made neutral to litmus paper with ammonia water, a white material is precipitated which is 2-amino-4- (4'-arsinosoanilino) pyrimidine monohydrate.

ASO.H2O

IIIH

2-amino-4-(4-arsinosoanilino) pyrimidine monohydrate Analysis: As; found, 25.4%; required by the formula, 25.5%.

In place of 2-amino-4-(4-arsonoanilinol;--pyrimidine, any of the products described in Examples 1, 2, 3 or 4, or any similar products,-'may be substituted in Example 5 to give the corresponding dichloroarsines and arsine oxides coming under the general formula for the new products.

- Example 6 2-amino-4- (4- arsinosoanilino) pyrimidine and two moles of thioglycollic acid or 2-amino-4-(4' arsonoanilino) pyrimidine and four moles 01 thioglycollic acid are dissolved in an excess. oi sodium hydroxide solution. The solution is acid v ified and the resultingprecipitate washed-repeati edly with water. It .is 2-amino-4-[4'-di-(carboxymethylenethio) arsinosoanilino] pyrimidine 2-emino-yl-14'.di-(,carhoxymethylenethio) arsinosoanilino] pyrimidine" sents one of the pentavalent' arsenic groups arse-ices:

on dissolving the above;- Product-inalkalf such lliS(SCH2000NaM 7 I N '7 v A N J mie" j v A H i V J-NH2 I i V V t f j N and their'I-I'A" acid addition salts, where Xisas 2-amino-4-[4-di-(sodium carboxymethylnethio) arsinosoanilino] pyrimidine When other sulfhydryl compounds are used in place of thioglycollic acid, corresponding deriva-: tives are obtained. For example, cysteine gives ens-onen-boom:

2-a-mino-4-[4-di-(fl-carboxy-fl-aminoethylthin) arsinosoanilino] pyrimidino and glutatlnone gives J-NH2 V l N w i 2-amino4-(4-diglutathienylarsinosoanilino) pyrimidine .f i

The arsono compoundsof the inventionareof: 60

especial value since they not onl'y embod ycom pounds valuable as: therapeutic agents, but include compounds which may serve as intermediates for compounds of therapeutic value. For example, arsono compounds of the formula,

and their HA acid addition salts, -where A renre- 70 r A a reduced in presence of.' middle" halogen acid to give the corresponding trivalent arsenicalcom poundsand their hydrohalides, where A is'one of '--AsCl2, AsBrz, and (by simple: neutralization) AsO and As(OI-I)"z. In this way-'thereare obtained the valuable arsenical's'of formula defined in the general'formula and where A is a -As(OH) 2, the group- A" being" the: anion of an acid having" a dissociation constant o-fatileas't AsCl2 and -Br whenever A is AsBrz.a

What'we claim asour invention is: 1 A" compound of the formula.

acid having a dissociation constant. of .at least and M is a basic=salti-;forming. group;-

2. A compound of the formula and'its acid addition salts, whereAf is the of'at least 10* jA' isan a rs'enical ,g ro'upingo'fthe class consisting of --ASO3H2, As'O1=iI-IM,

3. A compound of'the formula N A NH- he,

and itsiHAf acid addition salts, :where A the anion of an acid having aidissociationconstant;

of at least 10 A is an arsenicaligrouping of the class consisting of -As0'a'H2, AsOsHM, ASO3M2, -AsO "*--As(SCH2COOH) 2, and

-As(SCHzCO0M-)'z, and Misc, .basio salt-forming group. n

4. Acompound oftherformula I o I its V e N 7 7 about" 10-' and being Cl whenever A' isanion of an acid having a dissociation" constant and its acid addition sa l'tsiwh erea Austria-1 anion of an acid having a dissociation constant of at least 10 and A is AsO3H2 and its salts.

5. A compound of the formula where A is ASO3H2 and its salts. 6. A compound of the formula and its HA acid addition salts, where A is the anion of an acid having a dissociation constant of at least 10 7. A compound of the formula N M W i a 8. A compound of the formula N some OM) =AsONH NJNH1 and its HA acid addition salts, where A is the anion of an acid having a dissociation constant of at least 10- and M is a member of the class consisting of H and a basic salt-forming group.

9. A compound of the formula somcooM AS-ONH NJ-NH where M is a member of the class consisting of H and a basic salt-forming group.

10. Process for the preparation of anilinopyrimidine arsenicals which comprises reacting an anilino arsenical compound of formula with a pyrimidine compound of formula where Y is a member of the class consisting of -H, NH2, -Cl, -Br, -alkyl, and -alkylene- 14. OH, Z is a member of the class consisting of ,--Cl and -Br, A is a member of the class consisting of --AsO3H2, ASO3HM and -AsO3Mz. and M is a basic salt-forming group.

11. Process for the preparation of anilinopyrimidine arsenicals which comprises reacting an anilino arsenical compound of formula with a pyrimidine compound of formula where Z is a member of the class consisting of -C1 and -Br, A is a member of the class consisting Of ASO3H2, --AsO3I-IM and -ASO3M2, and M is a basic salt-forming group.

12. Process for the preparation of anilinopyrimidine arsenicals which comprises reacting an anilino arsenical compound of formula with a pyrimidine compound of formula with a pyrimidine compound of formula Z J NE:

where Z is a member of the class consisting of -C1 and -Br, A is a member of the class consisting of --AsO:;Hz, -AsO3HM and -ASO3M2, and M is a basic salt-forming group.

CLIFF STRUTHERS HAMILTON. CLARENCE KENNETH BANKS. 

